MICRO-CLIMATE AND MOBILITY OF A BARCHAN DUNE IN THE THAR DESERT

The thermal, soil moisture and wind regimes across a barchan in the we stern part of the Thar desert were studied for three years in relation to the geomorphological properties of the dune and iis movement. A cl ose cause and effect relationship was observed between the wind charac teristics, air temperature and dune shape. Spatio-temporal variation i n the net radiation and heat flux from the dune body were also analyse d. Wind speed and the sand transportation rate on the dune were very h igh during the peak summer months, leading to faster movement of the d une. The average rate of movement of the barchan during the recorded p eriod was 31.7 m per year, but there was significant yearly variation, depending upon the rainfall condition in the previous monsoon season and the wind speed during the current summer.